Serogroup B and C strains of Neisseria meningitidis (Nm) together account for the majority of invasive diseases in Europe and the United States. Vaccines against individual Nm serogroups are presently available. The NmB vaccine from the Norwegian National Institute of Public Health is safe, elicits strain-specific immunity in children and adults, and is efficacious in preventing NmB disease in adolescents. This vaccine has typically been combined with meningococcal C polysaccharide vaccine and given with alum. The plain polysaccharide vaccine component, however, is not effective in infants and young children. The Chiron NmC conjugate (conj.) vaccine is also safe, elicits high titres of serum bactericidal antibody in infants vaccinated as young as two and three months of age, and induces immunologic B cell memory to the unconjugated NmC polysaccharide.
To provide a combination vaccine for NmB and NmC which induces an immune response to both serogroups, international patent application WO99/61053 discloses immunogenic compositions that comprise (a) NmC oligosaccharide conjugated to a carrier, in combination with (b) NmB outer membrane protein. The combination vaccine induces an immune response to both serogroups that is not significantly different from the immune response induced by each serogroup alone. It is an object of the present invention to develop these into compositions that induce immune responses against a wider variety of organisms.